Composite support and uses

ABSTRACT

A composite support includes a first layer or sheet made from a printable or dyed material, a second layer or flexible polymer layer, and a third layer made from a hydrophilic and film-forming polymer. A method of using the support, in particular in digital printing or in dyeing with sublimation dyes, is also disclosed.

The invention relates to a support for the production, in particular of printed and/or dyed visuals, intended for communication, such as posters, backlit signs, flags, banners, but also printed and/or dyed furnishing textiles, such as curtains, wall coatings, walls and stretch ceilings.

Digital printing has superseded traditional printing methods, and in particular screen printing or offset printing methods, making it possible, with methods which are a lot quicker and more flexible, and therefore more profitable, to print any type of support, of any dimension, and to obtain a greater printing quality.

Digital printing with sublimation dyes which is the technique concerned by the invention, is a printing technique, mainly dedicated to textile printing and which uses aqueous inks. This technology consists of transforming, under the effect of heat, the dyes into gases and to make these penetrate into the fibres of the support. The textile preserves all of the features thereof and the printing obtained by this core dye is very water-resistant, resistant to mechanical stresses, to UV, among others. It makes it possible for a perfect restitution and luminosity of colours, a reproduction of high definition images, as well as a printing deeply inserted in the fibres of the support. This printing method resorts to non-polluting and harmless inks, which do not release any odours, nor VOCs.

By ink according to the invention, this means an aqueous dispersion of dyes, which could comprise any suitable additive and any suitable vehicle, and adapted to digital printing with sublimation dyes, therefore having thermoresistant properties. By dyeing, this means an aqueous dispersion of dyes, which could comprise any suitable additive and any suitable vehicle, and adapted to dyeing by sublimation of dyes.

Digital printing with sublimation dyes can be performed according to two methods, by transfer printing or by direct printing. Transfer printing involves an intermediate step of printing on a heat-resistant transfer paper in the form of an inverted image. The image is then transferred, by hot pressing, from the paper to the textile support. Direct printing consists of depositing the ink directly on the support, then of drying the ink to remove the aqueous solvent. In both cases, a sublimation step is then carried out at a temperature of 160 to 200° C., on a mat-heating calender for transfer and direct printing methods, and on a heating cylinder or under an infrared rail or by hot air convection for direct printing, leading to the durable bonding of dyes of the ink in the support. During this step, using coating supports can pose a problem as the coating can adhere to the calender and generate, in this, defects in the image.

Direct printing has the disadvantage of a risk of spreading of the ink before drying, also the support is subjected to a pre-treatment making it possible to retain the ink in the place where it has been deposited.

The printer has support rolls, for example textile, which can be white, neutral or transparent, to be printed. According to whether the support is pre-treated or not, and according to the printer fleet thereof, it opts for direct printing or transfer printing. The supports thus printed are then packaged and shipped.

Document EP1102682B1 relates to a transfer paper for textile printing, which in view of improving the dye transfer efficiency from the paper to the textile, comprises on the face of the paper to be printed, a layer called a barrier which makes it possible to avoid the spreading of the deposited ink and to increase the effectiveness of the transfer. This layer is made from a polymer such as a polyvinyl alcohol, a carboxymethylcellulose, an alginate and/or a gelatine.

Document EP2457737A1 discloses a composite support for offset printing, of which the resistance to water and to dust is reinforced. To this end, the composite support comprises a layer on either of the faces of which a porous pigment-based layer, a particulate latex-type polymer dispersion and a vinyl alcohol and alkylene copolymer is deposited.

A composite material intended for the production of containers, for example food containers is known according to document U.S. Pat. No. 7,320,825B2, and has a resistance to greasy environments. It comprises three layers, a lower paper layer, an intermediate layer made from a film-forming polymer devoid of any filler and an upper layer made from a film-forming polymer incorporating a lamellar mineral filler. This material therefore has a sealing to grease, but is not adapted to a printing or a dyeing according to the invention.

If these documents make it possible to improve the printing quality and/or the resistance of a support to certain factors, none prevents the migration of materials like sublimation printing dyes through the support.

This problem is encountered during packaging to ship printed or dyed supports, in particular during the printing of supports of large widths and therefore of large and very large surface areas.

Ideally, the visuals are rolled on a cardboard tube or with a protective paper. But, to limit the constraints and to save on material and transport costs, the visuals are usually shipped folded in an envelope, without protective paper between the folds. Under these contact conditions of the thicknesses together, a dye migration phenomenon is observed from the printed face of the support through the support to reach the other thicknesses. This phenomenon that is called ghost image greatly affects the quality of the image, in particular when the poster is intended to be backlit, ghost colours and patterns appearing in the lightest zones, and mixtures of dark dyes in light dyes occurring.

In addition, the support is generally coated, in view of giving it a resistance, for example, to climatic conditions, such as water, UV radiations, if it is intended for an outside display, or by an anti-stain, fireproof treatment, or any other treatment, in particular to improve the optical qualities of the support after printing. The presence of this coating reinforces the abovementioned packaging problem, as the coatings facilitate the migration of dyes.

Finally, the pressure and the temperature, from 30° C., are parameters which accelerate this process.

To date, the only solution available for the production of backlit display boards printed with sublimation dyes and not having ghost images, passes through using non-coated textiles having a very tight mesh so as to avoid the presence on the poster of light spots of the backlighting. However, it is not economically interesting, as the textile of a thread density of around 150 to 300 g/m², as well as the treatment thereof, for example, fireproof or other, are expensive particularly as part of a temporary use. In addition, the high material density requires powerful and therefore high energy-consuming illuminations in order to obtain a sufficient contrast effect.

In comparison, the coated textile support is more efficient, in terms of both the printing quality and light transmission, it therefore represents an economically more advantageous solution, but this solution clashes with the problem of the ghost image.

The invention brings a solution to this problem with a composite support which, after printing, can be packaged in a folded form without being concerned about the ghost image phenomenon.

The composite support of the invention comprises a sheet which can be printed or dyed by sublimation dyes, this sheet being pre-treated or not, a flexible polymer layer and a hydrophilic polymer film. The combination of the flexible polymer layer and the hydrophilic and film-forming polymer layer forms a barrier, perfectly sealed to the dyes, thus preventing the migration thereof, while maintaining the properties of the single support, and in particular the flexibility thereof. In addition, thanks to the hydrophilic polymer layer thereof, the composite support of the invention does not adhere to the hot calender during the sublimation step, which constitutes an additional advantage with respect to known supports.

Thus, the composite support of the invention comprises at least three layers: a first layer or sheet made from a material which can be printed or dyed by sublimation dyes, which has two faces, one upper face which will be that on which the ink(s) will be deposited and which will therefore be the printed face or face which is dyed, the other lower face which is in contact, direct or indirect, with a second layer or flexible polymer layer. This second layer itself also has two faces, one upper face oriented towards the lower face of the sheet and the other lower layer in contact, direct or indirect, with the third layer or hydrophilic polymer film.

The support of the invention advantageously responds to the following features, considered individually or in combination.

The hydrophilic and film-forming polymer of the third layer is selected from among vinyl alcohol polymers, vinyl alcohol and alkylene copolymers, such as vinyl alcohol and ethylene copolymers, carboxymethylcelluloses, hydroxypropylcelluloses, alginates, gelatines, polyvinylpyrrolidones, polyethyleneimines and copolymers comprising at least one of the monomers selected from among vinyl acetate, vinyl alcohol and ethylene, and any mixture of these polymers and copolymers.

The second layer has a solid structure such as a film or a honeycomb structure such as a foam.

The second layer comprises at least one polymer or a copolymer selected from among polyurethanes (PU), acrylic polymers and copolymers, polyvinylidene chloride (PVDC) and vinylidene chloride copolymers, polyvinyl acetate (PVAC), and any mixture of these polymers and copolymers.

The second layer comprises at least one additive such as an additive selected from among a fireproofing additive, a rheological additive like a thickener, a surfactant, a brightening additive, and/or at least one filler and/or at least one pigment.

The proportion of polymer or copolymer in the second layer is at least 20% (wt/wt) and at most 99% (wt/wt), wt/wt meaning by polymer or copolymer weight with respect to the weight of the second layer.

The second layer has a thickness of at least 5 μm, preferably at least 7 μm and/or at most 30 μm, preferably at most 15 μm.

The second layer has a weight of between 10 and 100 g/m², preferably of between 50 and 70 g/m².

The first layer is made from a fibrous or non-fibrous material, printable or made printable and/or printed and/or dyed, said material being selected from among any polymer, any copolymer, any mixture of polymers and/or copolymers, of natural or synthetic origin.

The material of the first layer is selected from among polyesters, polyamides, mixtures of these polymers, but also mixtures of these polymers with other polymers or copolymers or materials like cotton, non-printable with sublimation dyes.

The material of the first layer is textile, of woven or non-woven type, knitted type, or a mixture of woven, non-woven and/or knitted type.

The textile is a polyester woven textile.

The first layer is pre-treated by a primer for preparing for direct printing or by a coating.

The invention also relates to a method for producing a composition support of the invention, said method comprising the following steps:

-   -   A first layer or sheet is arranged such as described above,         treated or not, having an upper face which will be printed or         which is dyed with sublimation dyes,     -   On the lower face of the first layer, an aqueous polymer paste         is applied by any technique known to a person skilled in the         art, to obtain, after drying a second layer or flexible polymer         layer such as defined above, having an upper face adhering to         the lower face of the first layer, and a lower face,     -   On the lower face of the second layer, a solution of a         film-forming hydrophilic polymer is applied, to obtain a third         layer such as defined above.

The invention also relates to uses of a composite support such as described above. Such a support can indeed be dyed or intended to be printed by digital printing with sublimation dyes.

In the case of a first layer dyed by sublimation dyes, it can have uses like stretch ceilings and stretch walls.

Before describing the invention in more detail, the definition of terms used in the present text is indicated below.

By treated or pre-treated layer or material, a layer or a material is understood, which has undergone one or more operations, generally by exposure to one or more chemical and/or physical agents, in order to give this layer or this material one or more properties that it does not have, to reinforce or on the contrary weaken one or more of the properties that it has. Enter into this definition, any treatment of a layer intended to be printed, for example, by direct printing, as well as any treatment of a layer to give it fireproof properties, optical properties, acoustic properties. These operations are known to a person skilled in the art, the treatment agents of course depend on the expected printing or dyeing qualities and performances of the layer or material sought and implemented by conventional techniques, for example, of coating or impregnation type.

By flexible polymer layer, this means a layer which mainly comprises one or more polymers having a glass transition temperature, Tg, lower than 0° C., this temperature being measured by any technique known to a person skilled in the art, like for example the DSC (Differential Scanning Calorimetry) method.

By film-forming polymer, this means a polymer which, after use in the state of a solution or dispersion, forms on the layer on which it is applied a continuous and adherent film.

The three main layers constituting a composite support 1 according to the variants of the invention are described below in more detail, and in support of FIGS. 1 and 2, without however the invention being restricted to this. These embodiments are particularly adapted to the production of backlit signs, but of course, other embodiment entering into the scope of the invention, but not expressly described below, can be implemented, according to the printing or dyeing qualities sought.

FIG. 1 represents, in a cross-section, a composite support 1 intended for a transfer printing with sublimation dyes. It comprises a first layer 2 made from a non-pre-treated polyester textile, a second layer 3, for example made from a fireproofed foam and a third layer 4 made from a vinyl alcohol polymer.

FIG. 2 represents, in a cross-section, a composite support 1 intended for a direct printing with sublimation dyes. It comprises a first layer 2 made from a polyester textile pre-treated with a primer for preparing for direct printing, a second layer 3, for example made from a fireproofed foam and a third layer 4 made from a vinyl alcohol polymer.

FIRST LAYER OR SHEET 2

The sheet 2 is made from a material which can be printed by sublimation. This material can be fibrous, in the form of more or less long fibres, like a textile, or non-fibrous. It can be selected from among any polymer, any copolymer, any mixture of polymers and/or copolymers, of natural or synthetic origin, printable or made printable. Advantageously, it is selected from among polyesters, polyamides, mixtures of these polymers, but also mixtures of these polymers with other polymers or copolymers or materials like cotton, non-printable with sublimation dyes. If it is textile, it can be of woven or non-woven, knitted type, or a mixture of woven, non-woven and/or knitted type. Preferably, the material is a textile of polyester fibres and even better, it is a polyester woven textile.

Enters into the field of the invention, any sheet of a material such as described above and further comprising any additive, for example incorporated during the production of the sheet, and/or any treatment or pre-treatment, for example applied on one 5 and/or the other 6 of the faces of the sheet 2. As an example, the sheet 2 can comprise a fireproofing agent which is distributed in the polymer(s), of which one or the two faces 5, 6 of the sheet 2 have been coated. Also, the upper face 5 of the sheet 2 can have undergone a pre-treatment, in particular in view of a direct printing, and this in order to avoid the diffusion of the ink deposited on the sheet. Pre-treatment products are available commercially and in particular the following: the product Thermacol® MP (commercialised by Huntsman), the product AboPrint FX (commercialised by Bodewes Material Solutions) and the product Luprejet HD (commercialised by BASF). They are applied by padding, spraying, reverse roll coating, slot-die, knife coating and any other technique known to a person skilled in the art.

The lower face 6 can also be treated in view of improving the adhesion of the second layer.

Any treatment of the lower face 6 of the sheet 2 can, in addition, prevent the polymer layer from passing through the first layer 2 during the deposition thereof.

According to a preferred embodiment, the first layer or sheet 2 has a thickness of at least 20 μm.

Advantageously, it has a weight which is at least 20 g/m², preferably at least 55 g/m² and/or at most 150 g/m², preferably at most 120 g/m², and even better, at most 70 g/m².

Second Layer or Flexible Polymer Layer 3

The flexible polymer layer 3 is produced from any polymer, any copolymer, any mixture of polymers and/or copolymers, chemically and physically compatible with the first 2 and third 4 layers, capable of adhering the first 2 and third 4 layers and not substantially affecting the flexibility of the first layer 2. Advantageously, it has a honeycomb structure of foam type, it can also have a solid structure, for example of film type. It preferably comprises at least one polymer or a copolymer selected from among polyurethanes (PU), polymers and copolymers obtained from monomers of which at least one is selected from among acrylic, styrene, butadiene, acrylonitrile, vinyl, ethylene, polyvinylidene chloride (PVDC) and polyvinyl acetate (PVAC), copolymers of vinylidene chloride and one of the monomers described above. Such polymers are available commercially, as examples of commercial polymers, the following can be cited: Plextol DV 245 (Synthomer), Texicryl 13-500 (Scott Bader), Appretan® E4250 (Archroma), Appretan® N52281 (Archroma), Primal E 941 P (Dow), Encor® 1103 (Arkema), Encor® 1220 (Arkema), Hystretch® 7318 (Lubrizol) for acrylic (co)polymers, Rolflex SW3 (Lamberti), Rolflex BZ 78 (Lamberti), Lurapret® NDPS (Archroma) for polyurethanes, Acronal® S 560 (BASF) like acrylate, styrene and acrylonitrile copolymer, Diofan® A 036 (Solvay) for PVDC, Vinnapas® EN 428 (Wacker) for PVAC, Vinnol® CEN 2752 (Wacker) for vinylidene chloride copolymers.

It can also comprise at least one additive, for example one or more additives selected from among fireproofing additives, rheological additives like a thickener, surfactants, brightening additives. It can also comprise at least one filler and/or at least one pigment.

Thus, to meet fire protection standards, the flexible polymer layer 3 preferably contains fireproofing additives or flame retardants. As examples, such additives can be selected from among organic phosphates like melamine polyphosphate, mineral phosphates like ammonium polyphosphate, phosphonates, phosphinates, metal hydroxides like aluminium trihydroxide, magnesium hydroxide, antimony oxides like antimony trioxide, stannates like zinc stannate and zinc hydroxystannate, borates like zinc borate, derivatives of melamine like melamine cyanurate, halogenic derivatives like polybromodiphenyls, polybromodiphenylethers, polybromodiphenylethane like decabromodiphenylethane. Ideally, when the composite support of the invention is intended for the printing of large surface areas, for example intended for public establishments, fireproofing properties must reach a level M1 according to the French standard NF P92-507 and B1 according to the German standard DIN 4102, these standards being given for information purposes, being understood that any other standard in force according to the country of use can be used as reference.

The second layer 3 advantageously comprises at least one filler and/or at least one pigment. As an illustration, when the sheet on which it is bound is white, the filler is selected from among light materials such as calcium carbonate, silica. It can also be selected from among any natural or synthetic white pigments, like certain metal oxides, for example titanium dioxide, zinc oxide, or like lithopone, which will bring optical properties and which can furthermore fulfil the filler function.

The second flexible polymer layer 3 is, according to a preferred variant, a foam. Indeed, it will make it possible to facilitate the emission of gases, in particular during the sublimation of dyes, but also to optimise the diffusion of light, in particular when the composite support of the invention is intended for the printing of backlit posters. With this aim, it will be preferred that the refining time of the foam which makes it possible to control the size of the distribution of cells in the foam is of between 1 and 2 minutes, preferably 2 minutes. Thus, complementing the barrier effect thereof when it is combined with the third layer, this foam must ensure an optical diffusion of light specifically in the case of backlit supports, the light transmission preferably being of between 20% and 50% and preferably between 30-35%, when it is measured according to an adapted method of the standard NF G07-162. To this end, this second layer 3 preferably has a thickness of at least 5 μm, preferably at least 7 μm and/or at most 30 μm, preferably at most 15 μm.

According to an advantageous structure of a composite support 1 of the invention, the second layer 3 has, in the wet state, a density of at least 150 g/L, preferably at least 200 g/L and/or at most 350 g/L, preferably at most 220 g/L. Beyond 350 g/L, the support loses the flexibility thereof, and below 200 g/L, the barrier effect of the combination of the second 3 and third 4 layer is weakened.

If the second layer 3 can comprise no additive, nor filler, nor pigment, the proportion of the polymer(s) and/or of the copolymer(s) is advantageously at least 20% (wt/wt) by weight with respect to the weight of the layer and at most 99% (wt/wt) by weight with respect to the weight of the layer. Indeed, to obtain the ideal optical properties and the required fireproofing properties, the second layer comprises at least one filler and or suitable additive(s). It is however preferable that the proportions thereof do not exceed 80% (wt/wt) at the risk of losing flexibility and cohesion.

The second layer 3 is generally obtained from a polymer composition in the aqueous phase in the form of paste or foam which is applied on the lower face of the textile by any technique making it possible to obtain a homogenous layer which has a smooth lower face, such that the third layer 4 can be applied there. As an example, the foam layer is applied by knife over roll coating.

This second layer has a weight of between 10 and 100 g/m², preferably of between 50 and 70 g/m².

Third Layer Called Hydrophilic Polymer Film or Hydrophilic and Film-Forming Polymer Layer 4

As said above, the combination of the second layer 3 and the third layer 4 constitutes a barrier to any migration of dyes.

Insofar as the second 3 and third 4 layers together form the sealing barrier to the migration of dyes, the third layer 4 is made from a hydrophilic and film-forming polymer which can be selected from among vinyl alcohol polymers, vinyl alcohol and alkylene copolymers such as vinyl alcohol and ethylene copolymers, carboxymethylcelluloses, hydroxypropylcelluloses, alginates, gelatines, polyvinylpyrrolidones, polyethyleneimines and copolymers comprising at least one of the monomers selected from among vinyl acetate, vinyl alcohol and ethylene, and any mixture of these polymers and copolymers.

In a preferred embodiment of the invention, the polymer of this third layer 4 is selected from among polyvinyl alcohols, preferably having at least 50% of units [—CH₂—CH(—OH)—], advantageously at least 90%, even at least 95% and even better at least 98%, and vinyl alcohol and alkylene copolymers such as vinyl alcohol and ethylene copolymers. Such polymers are available commercially like the following products: JP18 (Japan Vam & Poval), JC33 (Japan Vam & Poval), Alcotex 72.5 (Synthomer), Poval® B33 (Denka), Poval® 28-99 (Kuraray), Poval® 56-98 (Kuraray), Poval® 15-99 (Kuraray), Selvol® 325 (Sekisui), Exceval® HR-3010 (Kuraray). Of course, any other PVA, having the same physicochemical features is adapted.

The polymer and in particular, vinyl alcohol polymer is deposited from an aqueous solution having a dry extract (DE) in said polymer of between 1 and 50%, preferably between 5 and 10% (wt/wt); the lower limit corresponds to the minimum quantity making it possible to obtain a barrier effect and the upper limit corresponds to the maximum quantity making it possible to preserve the flexibility of the support and the permeability thereof.

The PVA selected has a molar mass making it possible to have, for a DE of 5-10%, a viscosity adapted to the deposition method. Any other PVA responding to this feature can suit this method of use of knife over air coating type. It is down to the skills of a person skilled in the art to incorporate any additive necessary for the implementation of the method of use or facilitating it. Thus, in view of an optimal result, the method of use by knife over air coating requires additives of spreading agent type to improve the quality of the film, and possibly drying retardant agents.

This third layer 4 is deposited by knife over air coating with knife profiles having a diameter of between 2 and 20 mm and having a surface state making it possible to deposit the desired quantity without defecting the appearance and function.

Any other deposition technique (reverse roll, slot-die, spraying, kiss-roll and other techniques) known to a person skilled in the art, making it possible to deposit the desired quantity without defecting the appearance and function can be used and can lead to the possibility or the necessity to use a PVA grade, different in terms of molar mass.

According to an advantageous variant of the invention, the composite support 1 furthermore has a certain permeability to air, to make possible the release of gases released during the sublimation step: that is why, a permeability greater than 0.5 L/m²/s under a pressure different of 2500 Pa is preferred.

The production of a support such as described above comprises the following steps:

-   -   A first layer or sheet 2 is arranged such as described above,         treated or not, having an upper face 5 which will be printed or         which is dyed with sublimation dyes,     -   On the lower face 6 of the first layer 2, an aqueous polymer         paste is applied by any technique known to a person skilled in         the art, to obtain, after drying a second layer or flexible         polymer layer 3, having an upper face 7 adhering to the lower         face 6 of the first layer 2, and a lower face 8, and     -   On the lower face 8 of the second layer 3, a solution of a         film-forming hydrophilic polymer is applied, to obtain a third         layer 4.

It is illustrated in example 1 below, and the anti-migration properties of the composite support thus obtained are highlighted in example 2, in reference to following FIGS. 3, 4 and 5:

FIG. 3 represents a stack of supports comprising a composite support of the invention, for anti-migration testing purposes.

FIG. 4 represents a folding in two of the stack of FIG. 3.

FIG. 5 represents what it observed after unfolding the folded stack of FIG. 4 having undergone an accelerated ageing in a heat chamber.

Example 1: Production of a Composite Support According to the Invention

A textile sheet 2 made from woven polyester fibres is arranged, having a weight of 63 g/m² and intended for a transfer printing with sublimation dyes.

To prepare the second layer 3, a polymer paste is produced from the ingredients mentioned in table 1 below:

TABLE 1 Ingredients Function % (wt/wt) Encor ® 1220 Binder 35.0  (Acrylic copolymer) Aluminum trihydrate Fireproofing additive 50.5  CaCO₃ White pigments  5.8  Na sulfosuccinamate Surfactants  4.45 Ammonium stearate Acrylic thickener Thickener  4.25

The polymer paste is prepared by dispersion in the aqueous phase under mechanical stirring as follows:

-   -   Dispersion of the fillers in the presence of suitable additives     -   Adding to the filler dispersion, binder, water and additives         making it possible to obtain the properties sought (pH,         viscosity, dry extract)     -   Mechanical foaming of the paste: injection of air. Then refining         for 1 to 2 minutes.

It is then applied on the lower face 6 of the first layer 2.

Then, a vinyl alcohol polymer solution is prepared from the ingredients mentioned in table 2 below:

TABLE 2 Ingredients Concentration in % (wt/wt) Water 92.5 Poval ® 28-99  7.3 (Polyvinyl alcohol) Biocide agent  0.2

This composition is applied on the lower layer 8 of the second layer 3, then dried.

The same method is carried out on a textile support made from woven polyester fibres, having a weight of 63 g/m², said textile support having been pre-treated in view of a direct printing.

Example 2: Production of Another Composite Support According to the Invention

A textile sheet 2 made from woven polyester fibres is arranged, having a weight of 80 g/m² and intended for a transfer printing with sublimation dyes.

To prepare the second layer 3, a polymer paste is produced from the ingredients mentioned in table 3 below:

TABLE 3 Ingredients Function % (wt/wt) Acrylic copolymer Binder 44.6 Sodium sulfosuccinanate Surfactant  9.2 Ammonium stearate Antimony trioxide Fireproofing filler 12.8 Decabromo diphenyl ethane Fireproofing filler 26.2 Melamine formaldehyde Cross-linking agent  3   Ammoniac Neutralisation agent  0.2 Acrylic thickener Thickener  4  

The polymer paste is prepared by dispersion in the aqueous phase under mechanical stirring as follows:

-   -   Dispersion of the fillers in the presence of suitable additives     -   Addition to the filler dispersion of the binder, water and         additives making it possible to obtain the properties sought         (pH, viscosity, dry extract)     -   Mechanical foaming of the paste: injection of air. Then refining         for 1 to 2 minutes.

It is then applied on the lower face 6 of the first layer 2.

Then, a vinyl alcohol polymer solution is prepared from the ingredients mentioned in table 4 below, according to two different compositions (composition 1 and composition 2):

TABLE 4 Concentration in % (wt/wt) Ingredients Composition 1 Composition 2 Water 92.5 83.1 Poval ® 28-99  7.3 / (Polyvinyl alcohol) Poval ® 15-99 / 16.7 (Polyvinyl alcohol) Biocide agent  0.2  0.2

These compositions are then each applied on a lower layer 8 of the second layer 3 then dried to obtain two composite supports of the invention, one of which, the second layer 3 is treated by the composition 1, the other of which, the second layer is treated by the composition 2.

Example 3: Highlighting of the Anti-Migration Effect Through a Composite Support According to the Invention

According to FIG. 3, a stack of supports obtained by superposition from the bottom to the top of the three following support samples is arranged:

-   -   a composite support 1 of the invention such as described in         example 1 not printed, comprising from the bottom to the top of         this stack, a first layer or sheet 2 made from woven polyester,         a second layer or flexible polymer layer 3 and a third layer or         hydrophilic and film-forming polymer layer 4.     -   a composite support 1 of the invention such as described in         example 1 comprising from the bottom to the top of this stack, a         third layer or hydrophilic and film-forming polymer layer 4, a         second layer or flexible polymer layer 3 and a first layer or         sheet 2 made from woven polyester, said support 1 having been         printed with sublimation dyes 10; and     -   a support 13 comprising a first layer or sheet 2 made from woven         polyester on which a coating 11 has been applied, the coating         having fireproof and optical properties.

According to FIG. 4, a folding in two of the stack of FIG. 3 is proceeded with, and this arrangement is placed in a heat chamber at 50° C. for 4 days between two pressurised stainless steel plates 12.

For the clarity of FIGS. 3 and 4, the different stacked layers are represented contactless with one another, in the reality of the test, they are, of course, in contact.

A control stack not represented in the figures is arranged, constituted from the bottom to the top as follows:

-   -   a coated, woven polyester support, the coating having fireproof         and optical properties identical to the support 13 of the stack         represented in FIG. 3; and     -   one same coated, woven polyester support, the coating have         fireproof and optical properties, identical to the support 13 of         the stack represented in FIG. 3, said support being printed with         sublimation dyes 10, and     -   one same coated, woven polyester support, the coating have         fireproof and optical properties, identical to the support 13 of         the stack represented in FIG. 3.

This control stack, with an orientation of the supports identical to that presented in FIG. 3, is folded in two then subjected to the same accelerated ageing in the heat chamber.

The two folded and treated stacks are unfolded and the observation which is made of it is illustrated in FIG. 5.

In this FIG. 5:

-   -   the left-hand section relates to the control stack and the         right-hand section relates to the stack of FIGS. 3 and 4;     -   the upper section relates to the printed supports (at the centre         of the stacks) of the control stack (printed support 13) and         test stack (printed support 1) after accelerated ageing and         unfolding; the lower section relates to the control support         (support 13) or composite support (support 1), situated at the         bottom of the control stack (support 13) and test stack (support         1) after accelerated ageing and unfolding.

It is observed on the lower left-hand section, a ghost image which results from a migration of dyes, while on the lower right-hand section, the support remains blank, demonstrating the effectiveness of the barrier function of the combination of the second and third layers, preventing the migration of dyes through the support. 

1. A composite support comprising: a first layer or sheet made from a printable material; a second layer or flexible polymer layer; and a third layer or hydrophilic and film-forming polymer layer.
 2. The support according to claim 1, wherein the hydrophilic and film-forming polymer is selected from among vinyl alcohol polymers, vinyl alcohol and alkylene, carboxymethylcelluloses, hydroxypropylcelluloses, gelatines, alginates, polyvinylpyrrolidones, polyethyleneimines and copolymers comprising at least one of the monomers selected from among vinyl acetate, vinyl alcohol and ethylene, and any mixture of these polymers and copolymers.
 3. The support according to claim 1, wherein the second layer has a solid structure or a honeycomb structure.
 4. The support according to claim 2, wherein the second layer comprises at least one polymer or a copolymer selected from among polyurethanes (PU), acrylic polymers and copolymers, polyvinylidene chloride (PVDC) and vinylidene chloride copolymers, polyvinyl acetate (PVAC), and any mixture of these polymers and copolymers.
 5. The support according to claim 1, wherein the second layer comprises at least one additive selected from among a fireproofing agent, a rheological additive, a surfactant, a brightening additive, and/or at least one filler and/or at least one pigment.
 6. The support according to claim 1, wherein the proportion of the polymer or copolymer in the second layer is at least 20% (wt/wt) and at most 99% (wt/wt) by weight with respect to the weight of the layer.
 7. The support according to claim 1, wherein the second layer has a thickness of at least 5 μm and/or at most 30 μm.
 8. The support according to claim 1, wherein the second layer has a weight of between 10 100 g/m².
 9. The support according to claim 1, wherein the first layer is pre-treated by a primer for preparing for direct printing or by a coating.
 10. A method comprising using the support according to claim 1, wherein the support is dyed or intended to be printed by digital printing with sublimation dyes.
 11. The support according to claim 2, wherein the vinyl alcohol and alkylene copolymers are vinyl alcohol and ethylene copolymers.
 12. The support according to claim 3, wherein the solid structure is a film and the honeycomb structure is a foam.
 13. The support according to claim 5, wherein the rheological additive is a thickener.
 14. The support according to claim 1, wherein the second layer has a thickness of at least 7 μm and/or at most 15 μm.
 15. The support according to claim 1, wherein the second layer has a weight of between 50 and 70 g/m².
 16. The support according to claim 2, wherein the second layer has a solid structure or a honeycomb structure.
 17. The support according to claim 3, wherein the second layer comprises at least one polymer or a copolymer selected from among polyurethanes (PU), acrylic polymers and copolymers, polyvinylidene chloride (PVDC) and vinylidene chloride copolymers, polyvinyl acetate (PVAC), and any mixture of these polymers and copolymers.
 18. The support according to claim 2, wherein the second layer comprises at least one additive selected from among a fireproofing agent, a rheological additive, a surfactant, a brightening additive, and/or at least one filler and/or at least one pigment.
 19. The support according to claim 3, wherein the second layer comprises at least one additive selected from among a fireproofing agent, a rheological additive, a surfactant, a brightening additive, and/or at least one filler and/or at least one pigment.
 20. The support according to claim 4, wherein the second layer comprises at least one additive selected from among a fireproofing agent, a rheological additive, a surfactant, a brightening additive, and/or at least one filler and/or at least one pigment. 